The present invention relates to particle beam irradiation systems suitable for particle beam therapy using such a charged particle beam (ion beam) as of protons or heavy ions. More particularly, the invention is directed to a particle beam irradiation system configured to achieve beam energy change control and operating cycle update within a short time, and to a method for operating the system.
Particle beam therapy, a treatment performed upon the cancer in a patient by irradiating the affected region with such an ion beam as of protons or heavy ions, is known as radiation therapy for cancer. Useable methods for ion beam irradiation include such a scanning irradiation method that is disclosed in REVIEW OF SCIENTIFIC INSTRUMENTS, VOLUME 64, NUMBER 8 (AUGUST 1993), pp. 2074-2093 (hereinafter referred to as Non-Patent Document 1).
In addition, examples of a control method that realizes the beam energy change control required in a scanning irradiation method within a short time when a synchrotron is employed as an ion beam generator, include such multi-energy extraction control operation that is disclosed in JP-4873563-B and JP-2011-124149-A as well as Nuclear Instruments and Methods in Physics Research, A624 (2010), pp. 33-38 (hereinafter referred to as Non-Patent Document 2). In the multi-energy extraction operation, irradiation of ion beams of a plurality of energy levels is achieved within one operating cycle of the ion synchrotron.